Thank You very much for information. Your ideas seem to be a workaround for my problem.
However, I was looking for something a little bit different, because I didn't want to write any other component (or binding component), I simply wanted to adjust SMIX configuration to my needs. And now I know that it is rather impossible, because changing 'cxf/' in the URL involves recompiling 'Apache ServiceMix CXF Transport for OSGi' bundle.
Jean-Baptiste Onofré wrote
If you deploy the bundle in the NMR, you can expose the service using HTTP binding component (and so you can define the URI that you want).
To deploy the bundle in the NMR use address="nmr:HelloWorld" in the jaxws:endpoint and import cxf-extension-nmr.xml.
I'm going to add a tutorial in Jira explaining this.